Stereoscopic imaging is an imaging technique in which two cameras are used to record three-dimensional visual information. The first camera records a first image and the second camera records a second image which is slightly different from the first image. The first and second images are then combined to produce a three-dimensional image, i.e. a still three-dimensional image if the two cameras are still photography cameras or a three-dimensional video if the two cameras are video cameras.
To perform this technique, the cameras may be arranged in a setting known as a “beam splitter” setting, which has the advantage of enabling “close-up” shots at a relatively high level of zooming. In this setting, a beam splitting device, such as a half-silvered mirror, is placed at a predetermined angle, usually 45 degrees, in front of a subject. The beam splitting device enables a first portion of incoming light to be transmitted through it and a second portion of incoming light to be reflected on its surface. The first camera is positioned behind the beam splitting device in order to record the first image of the subject through the beam splitting device, while the second camera is placed perpendicularly to the first camera, usually above the beam splitting device, in order to record the second image of the subject reflected on the beam splitting device.
Various apparatuses have been devised to position the cameras relative to the beam splitting device in this setting. Usually, a frame structure is provided to maintain the cameras in position relative to the beam splitting device.
Unfortunately, most of the frame structures of the prior art do not allow the cameras to be properly supported. In some, each camera is mounted on a rail extending perpendicularly between a pair of parallel post members which define a support plane. The camera is therefore supported in a substantially cantilevered configuration by the post members. In this configuration, the weight of the cameras imposes a load on the post members, in a direction perpendicular to a longitudinal axis of the post members. This load may subject the post members to out-of-plane bending relative to the support plane and thereby cause deformations in the post members, especially when the frame structure is moved, for instance to record images of a moving subject.
Since precise positioning of the cameras is required to obtain a desired three-dimensional image, such deformations may require a user to periodically stop recording of the subject to readjust position of the cameras, which is costly and disruptive, and therefore cumbersome. Furthermore, images recorded using cameras mounted on such apparatuses may further require post-production operations to be performed on them in order to correct defects in the recorded images caused by deformations of the frame structure, which is also costly and time-consuming.
Other apparatuses of the prior art comprise a bulky and substantially heavy frame structure which is impractical and cumbersome, especially when the frame structure is moved or transported.
There is therefore a need for a frame structure which would overcome at least one of the above-identified drawbacks.
Features of the invention will be apparent from review of the disclosure, drawings and description of the invention below.